LostOPWiki: Thrust PID Scaling Setup
Thrust PID Scaling (TPS) is a mechanism to compensate for optimally tuned vehicles for hover or slow flight envelope by adjusting the PID (Proportional, Integral, Derivitave) value dynamically against a throttle position so that Fast Forward Flight (FFF) doesn't create oscillations It's important to perform basic tuning of your multirotor prior to enabling TPS functionality. Additionally, when implementing TPS, it is important to understand the relationship and configure the following curves/features in GCS: • Throttle Curve • Thrust PID Scaling Thrust PID scaling is available with Release 14.10 (MiniMe) and going forward. Throttle Curve – found on the Vehicle page of the Configuration gadget: Thrust PID Scaling – found on the Stabilization page of the Configuration gadget: Enable TPS – Check this box to enable Thrust PID Scaling Source – TPS may be configured for two distinct types of flight modes, manual or autonomous flight. Three configuration options are available to users in either flight mode: • ManualControlThrottle • StabilizationDesiredThrust • ActuatorDesiredThrust With manual flight or flights directly under operator control, all three modes will provide the same output setting to the PID's, as the actual "throttle setting" that is used in the scaling calculation. ActuatorDesiredThrust is recommended for flights predominately under manual control. Autonomous flight or flights under software control (AltitudeHold, Autonomous flight under automatic throttle control ), each option provides a scaling effect up or down to the PIDs, however, the point of application differs as follows: • ManualControlThrottle: uses commands received from the receiver • StabilizationDesiredThrust: uses commands computed by the Stabilization algorithm • ActuatorDesiredThrust: provide computed commands to the mixer Targets – • PID – Proportional, Integral, Derivative • PI – Proportional, Integral • PD – Proportional, Derivative • ID – Integral, Derivative • P – Proportional • I – Integral • D – Derivative Axis – • Roll Pitch Yaw • Roll Pitch • Roll Yaw • Roll • Pitch Yaw • Pitch • Yaw Thrust Axis – • X Axis (Thrust) represents the throttle position. • Each segment on the X axis represents 12.5% of the full throttle position; 12.5%, 25.0%, 37.5%, 50.0%, 62.5%, 75.0%, 87.5%, 100.0% Scale factor – • Y axis (Scale Factor) represents PID scaling • Above the X Axis Line is positive (+), below the line is negative (-) scaling to your current PID value(s) Procedure for setting TPS Configure your multirotor for optimal PID values with OPTune and ensure TPS is not enabled. Perform your standard tuning procedure to optimise the multirotor for normal flight. If you still experience instability of your multirotor, such as oscillations on full power climbs or fast descents, perform the following TPS procedure to minimize or eliminate the unwanted behavior. 1. Set the TPS hover point BEFORE you set the throttle hover point, by • Set main throttle curve to default with the “RESET” button. • Hover your quad to determine the throttle position for a stable hover. Result: Let's say it hovers at 40%... 2. Set the TPS curve so that it crosses the X-axis at 40% thrust. 3. Set the main throttle curve so that your quad hovers at 50% throttle. (Leave the TPS curve at 40%.) Problem Resolution • If you are experiencing oscillation at “low throttle” ie less than 50% you need to raise your PID’s scaling (+ PID Scaling). Low throttle is the left side of the TPS graph. • If you are experiencing oscillations at “high throttle” ie more than 50% you need to lower your PID's scaling (- PID Scaling). High throttle is the right hand side of the TPS graph. • The middle would be your hover range of throttle and the PID scaling should be really close to zero if not zero. * Refer to the TPS graph above for the quadrant descriptions. Examples Example 1 You're getting oscillations in fast forward flight, so you need to LOWER the PID’s. Therefore, LOWER the right side. Output example graph: Example 2 You're getting oscillations on descent / low throttle, you need to RAISE the PID’s. Therefore, RAISE the left side. Output example graph: LEFT SIDE = low throttle / descent (raise scaling to reduce oscillation) RIGHT SIDE = high throttle / FFF (lower scaling to reduce oscillation) • Adjust only one side at a time. • Test FFF and adjust for any oscillations, then come back and test quick descents and adjust accordingly. • Then test ALL: hover, FFF, and descent ... big smile awaits. Kategorie:OpenPilot Kategorie:LostOPWiki